1. Field of the Invention
The present invention relates to a fixture for fixing an article to be fixed, such as a workpiece, to a mounting object such as a fixture base or an MC pallet.
2. Background Art
A fixture shown in FIG. 21 (first fixture) is an example of a conventional fixture for mounting a workpiece on a mounting object such as a fixture base, an MC pallet, or a machine table, and fixing the workpiece thereto, while allowing access to surfaces other than the mounting surface of the workpiece. This fixture 40 was composed of a bolt 41 which is to be screwed into the lower surface serving as a mounting surface of a workpiece 45 and a body section 42 mounted on the mounting object 46. The body section 42 had a three-sided square shape in the longitudinal section, and the upper wall thereof was provided with a notch 43 for inserting the bolt 41. Further, the workpiece 45 was fixed to a plurality of body sections 42, 42 mounted on the aforementioned mounting object 46 by setting the workpiece 45 so that the female threaded portion 44 provided on the lower surface thereof was positioned above the notch 41, inserting the bolt 41 from below the notch 43, and screwing it into the female threaded portion 44 of the workpiece 45.
Another fixture (second fixture) was described in Laid-open Japanese Patent Application No. H9-285925 (FIG. 1 and FIG. 4). Thus, in this fixture, a ring-like drive member was inserted, so that it could move in the axial direction, in a portion close to the lower end of a guide hole opened at the upper end of a housing, and a transmission sleeve was inserted into a cylindrical hole of the drive member. This transmission sleeve was driven toward the lower end by the drive member and also was impelled upward by restoration means. Further, an operation tool was inserted into the upper end portion of the guide opening. By means of movement in the axial direction of the transmission sleeve with respect to this operation tool, this operation tool could switch an engagement tool supported in the upper end portion of the transmission sleeve between a position of engagement with the engagement portion of a clamp rod inserted in the cylindrical hole of the transmission sleeve and a position of disengagement from the engagement portion.
Then, a housing was mounted on a workpiece pallet, and a clamp rod was mounted on a workpiece. Here, the clamp rod was inserted into the housing and lowered. When the transmission sleeve was driven down by the drive member, the engagement tool was switched to the engagement position and engaged with the engagement portion of the clamp rod. As a result, the drive force of the drive member was transmitted to the workpiece via the transmission sleeve, engagement tool, and clamp rod in the order of description and the workpiece was mounted on the workpiece pallet and fixed thereto.